Acid mine drainage treatment material, method of preparing same, and use thereof
By calcining fly ash with Ca(OH)2 at high temperature to prepare acidic mine wastewater treatment materials, the problem of removing various heavy metals and inorganic salts from high-concentration acidic mine wastewater has been solved, achieving a simple and effective treatment effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINESE RES ACAD OF ENVIRONMENTAL SCI
- Filing Date
- 2023-10-24
- Publication Date
- 2026-07-14
AI Technical Summary
Existing technologies are ineffective in treating various heavy metals and inorganic salts, especially iron ions, manganese ions and sulfate ions, in high-concentration acidic mine wastewater. Furthermore, existing material preparation methods are complex and costly.
A high-concentration acidic mine wastewater treatment material was prepared by calcining fly ash and Ca(OH)2 at a high temperature of 600℃~800℃. This material is used to simultaneously remove iron and manganese ions and sulfate ions from the wastewater and increase the pH value of the wastewater.
It achieves efficient removal of various metals and inorganic salts from high-concentration acidic mine wastewater, simplifies the material preparation process, and reduces costs.
Smart Images
Figure CN117383678B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wastewater treatment technology, specifically to high-efficiency treatment materials for high-concentration acidic mine wastewater, their preparation methods, and applications. Background Technology
[0002] Coal is the world's most widely used and consumed basic energy source. Coal gangue is a solid waste discharged during coal mining and processing, accounting for 15% to 20% of raw coal production. The weathering of sulfur and sulfides in gangue piles produces acidic wastewater rich in sulfates, metals, and metalloids, known as acid mine wastewater (AMD). AMD is one of the most serious water pollution problems globally. Therefore, developing efficient remediation technologies for high-concentration acid mine wastewater and preparing corresponding environmental materials is of great significance for ensuring water quality safety and improving the water environment.
[0003] Fly ash is a fine ash collected from the flue gas after coal combustion during thermal power generation. Its main components are quartz and mullite, with approximately 57%–95% being SiO2 and Al2O3. Fly ash is an inexpensive, environmentally friendly, and potentially high-potential adsorbent. However, its low chemical activity and poor acid neutralization ability limit its application in AMD treatment.
[0004] Currently developed materials for treating acidic mine wastewater mainly include sulfate-reducing bacteria-supported immobilized particles and municipal solid waste pyrolysis ash composite materials, all of which have shown good treatment effects on acidic mine wastewater (CN 113354052B; CN 106861654 B). However, the preparation methods of these materials are relatively complex, and they have not been applied to the treatment of high-concentration acidic mine wastewater with multiple heavy metal concentrations above 100 mg / L. For example, sulfate-reducing bacteria-supported immobilized particles showed good heavy metal removal effects when treating acidic mine wastewater containing multiple low-concentration heavy metals with a maximum concentration of 40.4 mg / L, but their application in removing multiple metals from high-concentration acidic mine wastewater has not been carried out. Municipal solid waste pyrolysis ash composite materials can effectively increase the pH of acidic mine wastewater, but their application in removing heavy metals from acidic mine wastewater has not been carried out.
[0005] Therefore, developing simple, effective, and low-cost modification methods is of great significance for the efficient use of fly ash to treat high-concentration acidic mine wastewater. Summary of the Invention
[0006] This invention addresses the difficulty of simultaneously removing inorganic salts and multiple heavy metal ions from high-concentration acidic mine wastewater. By modifying fly ash with calcium hydroxide under suitable conditions, a treatment material for high-concentration acidic mine wastewater is obtained. This material can simultaneously remove SO4 from high-concentration acidic mine wastewater. 2-It can remove Fe and Mn ions and significantly increase the pH of wastewater. The preparation method is simple and shows good prospects for the simultaneous removal of polymetallic and inorganic salts in high-concentration acidic mining wastewater.
[0007] The purpose of this invention is to provide a high-concentration acidic mine wastewater treatment material, which is obtained by calcining fly ash and Ca(OH)2 at a high temperature of 600℃~800℃.
[0008] Another object of the present invention is to provide a method for preparing a high-concentration acidic mine wastewater treatment material, comprising:
[0009] (1) Collection and pretreatment of raw materials: fly ash is collected from the power plant, dried and sieved;
[0010] (2) Raw material compounding and roasting: The sieved fly ash is thoroughly mixed with analytical grade Ca(OH)2, and then roasted at a high temperature of 600℃~800℃, and then cooled naturally after roasting.
[0011] Another objective of this invention is to provide a high-concentration acidic mine wastewater treatment material for the simultaneous removal of multiple metals and inorganic salts from high-concentration acidic mine wastewater, wherein the multiple metals include iron ions and manganese ions, and the inorganic salt ions include sulfate ions.
[0012] This invention relates to a high-concentration acidic mine wastewater treatment material that can efficiently and simultaneously remove iron and manganese ions and sulfate ions when treating high-concentration acidic mine wastewater. It can also effectively reduce the acidity of the wastewater and increase the pH value, and has good application potential. Attached Figure Description
[0013] Figure 1 The XRD pattern of alkali-modified fly ash in the prior art is shown;
[0014] Figure 2 SEM images of alkali-modified fly ash in the prior art are shown;
[0015] Figure 3 The XRD patterns of raw fly ash, calcined modified fly ash, and Ca(OH)2 calcined modified fly ash according to a preferred embodiment of the present invention are shown.
[0016] Figure 4 The SEM images of raw fly ash (A, B), calcined modified fly ash (C, D), and Ca(OH)2 calcined modified fly ash of the preferred embodiment of the present invention (E, F) are shown.
[0017] Figure 5 The effect of Fe ion removal under different ash-to-calcium ratios is shown in Example 1;
[0018] Figure 6 The Mn ion removal effect under different ash-to-calcium ratios is shown in Example 1;
[0019] Figure 7 The effect of modified fly ash on Fe ion removal at different calcination temperatures is shown in Example 2;
[0020] Figure 8 The effect of modified fly ash at different calcination temperatures on Mn ion removal is shown in Example 2.
[0021] Figure 9 The effect of modified fly ash on Fe ion removal at different calcination times is shown in Example 3;
[0022] Figure 10 The effect of modified fly ash on Mn ion removal at different calcination times is shown in Example 3.
[0023] Figure 11 Example 4 illustrates the treatment of SO4 in acidic mine wastewater. 2- The removal effect;
[0024] Figure 12 The effect of Example 5 on improving the pH of acidic mine wastewater is shown. Detailed Implementation
[0025] The present invention will now be described in further detail with reference to the accompanying drawings and preferred embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.
[0026] Zhu Li et al. studied the effect of alkali-modified fly ash on Cr in wastewater 6+ The removal effect was good (Shanxi Chemical Industry, 2016, 36, 103-105), but the modified calcination temperature was low, resulting in differences in material structure and poor simultaneous removal of polymetallic and inorganic salts from high-concentration acidic mine wastewater. Its XRD and SEM images are shown below. Figure 1 and Figure 2 As shown.
[0027] The inventors discovered that by calcining a mixture of calcium hydroxide and fly ash at a high temperature of 600℃ to 800℃, particularly by programmed temperature rise calcination and calcination at a high temperature of 600℃ to 800℃, the XRD pattern of the obtained material ( Figure 3 ) and SEM image ( Figure 4 This indicates that the material surface and crystal phase structure are significantly improved, and it has an excellent removal effect on high concentrations of multi-metal ions, especially iron and manganese ions, while also having a good removal effect on sulfate ions.
[0028] Example
[0029] Example 1
[0030] Preparation of high-concentration acidic mine wastewater treatment materials: Collected fly ash was dried at 90℃, passed through an 80-mesh sieve, and mixed with different ash-to-calcium ratios (ash-to-calcium ratio 5:1 to 1:3). The mixture was placed in a co-rotating drum mixer and mixed for 2 hours. Then, it was placed in a tubular resistance furnace and heated to 600℃ at a heating rate of 5℃ / min. The mixture was calcined at 600℃ for 2 hours and then naturally cooled to room temperature to obtain high-concentration acidic mine wastewater treatment materials with different ash-to-calcium ratios.
[0031] Prepare a solution with Fe and Mn concentrations of 100 mg·L⁻¹. -1 For acidic mine wastewater: Weigh 0.482g of FeCl3·6H2O and 0.229g of MnCl2 into beakers, add distilled water and stir thoroughly until completely dissolved. Transfer all the liquid in the beakers to a 1000mL volumetric flask, then add distilled water to the volumetric flask until it reaches 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0032] High-concentration acidic mine wastewater treatment materials with different ash-to-calcium ratios were added to prepared acidic mine wastewater at a dosage of 20 g / L and stirred for 12 h. The removal effects of the materials prepared under different ash-to-calcium ratio compounding conditions on Fe and Mn ions were as follows: Figure 5 and 6 As shown in the figure, when the ash-to-calcium ratio is above 1:1, the simultaneous removal efficiency of Fe and Mn can reach 100%.
[0033] Example 2
[0034] Preparation of high-concentration acidic mine wastewater treatment materials: Collected fly ash was dried at 100℃, passed through a 90-mesh sieve, mixed with calcium ash at a 1:1 ratio, and placed in a co-rotating drum mixer for 3 hours. The mixture was then placed in a tubular resistance furnace, and the furnace temperature was raised to 600, 650, 700, 750, and 800℃ at a heating rate of 10℃ / min. The mixture was then calcined at 600, 650, 700, 750, and 800℃ for 3 hours, and then allowed to cool naturally to room temperature.
[0035] Prepare a solution with Fe and Mn concentrations of 100 mg·L⁻¹. -1 For acidic mine wastewater: Weigh 0.482g of FeCl3·6H2O and 0.229g of MnCl2 into beakers, add distilled water and stir thoroughly until completely dissolved. Transfer all the liquid in the beakers to a 1000mL volumetric flask, then add distilled water to the volumetric flask until it reaches 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0036] High-concentration acidic mine wastewater treatment materials prepared at different calcination temperatures were added to prepared acidic mine wastewater at a dosage of 30 g / L and stirred for 12 h. The removal effects of the materials prepared at different calcination temperatures on Fe and Mn were as follows: Figure 7 , 8 As shown in the figure, the materials calcined at 600, 650, 700, 750, and 800℃ all exhibited 100% simultaneous removal capacity for Fe and Mn.
[0037] Example 3
[0038] Preparation of high-concentration acidic mine wastewater treatment materials: Collected fly ash was dried at 110℃, passed through a 100-mesh sieve, mixed with calcium ash at a 1:1 ratio, and placed in a co-rotating drum mixer for 3 hours. Then, it was placed in a tubular resistance furnace, and the furnace temperature was raised to 700℃ at a heating rate of 10℃ / min. The furnace was then calcined at 700℃ for 0.5, 1, 1.5, 2, 3, and 4 hours respectively, and then naturally cooled to room temperature.
[0039] Prepare a solution with Fe and Mn concentrations of 100 mg·L⁻¹. -1 For acidic mine wastewater: Weigh 0.482g of FeCl3·6H2O and 0.229g of MnCl2 into beakers, add distilled water and stir thoroughly until completely dissolved. Transfer all the liquid in the beakers to a 1000mL volumetric flask, then add distilled water to the volumetric flask until it reaches 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0040] Materials prepared at different roasting times were added to the prepared acidic mining wastewater at a dosage of 20 g / L and stirred for 12 h. The removal effects of the materials prepared at different roasting times on Fe and Mn were as follows: Figure 9 , 10 As shown, the materials under all calcination times exhibited good effects on the simultaneous removal of Fe and Mn, with Fe removal rates of 100% and Mn removal rates of over 70%. The simultaneous removal effects of Fe and Mn were best when the calcination time was 2 hours or 4 hours.
[0041] Example 4
[0042] Preparation of high-concentration acidic mine wastewater treatment materials: The collected fly ash was dried at 100℃, passed through a 100-mesh sieve, mixed with calcium ash at a 1:1 ratio, and placed in a co-rotating drum mixer for 3 hours. Then, it was placed in a tubular resistance furnace, and the furnace temperature was raised to 700℃ at a heating rate of 10℃ / min. The furnace was then calcined at 700℃ for 2 hours and allowed to cool naturally to room temperature.
[0043] Calcination modified fly ash: The collected fly ash is dried at 100℃, passed through a 100-mesh sieve, placed in a tubular resistance furnace, and heated to 700℃ at a heating rate of 10℃ / min. It is then calcined at 700℃ for 2 hours and naturally cooled to room temperature.
[0044] NaOH modified fly ash: The collected fly ash was dried at 100℃, passed through a 100-mesh sieve, mixed with sodium ash at a 1:1 ratio, and placed in a co-rotating drum mixer for 3 hours. Then it was placed in a tubular resistance furnace, and the furnace temperature was raised to 700℃ at a heating rate of 10℃ / min. The furnace was then calcined at 700℃ for 2 hours and allowed to cool naturally to room temperature.
[0045] Preparation of SO4 2- Concentration of 1000 mg·L -1 For acidic mine wastewater: Weigh 1.479g of Na2SO4 and place it in a beaker. Add an appropriate amount of distilled water to dissolve it completely. Transfer the liquid in the beaker to a 1000mL volumetric flask, add distilled water to make up to 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0046] Preparation of SO4 2- Concentration of 1000 mg·L -1 The concentrations of Fe and Mn were both 100 mg·L⁻¹ -1 For acidic mine wastewater: Weigh 1.479g of Na2SO4, 0.482g of FeCl3·6H2O and 0.229g of MnCl2 into a beaker, add distilled water and stir thoroughly until completely dissolved. Transfer all the liquid in the beaker to a 1000mL volumetric flask, then add distilled water to the volumetric flask until it reaches 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0047] The prepared high-concentration acidic mine wastewater treatment material was added to the two types of acidic mine wastewater at a dosage of 20 g / L and stirred for 12 h.
[0048] Limestone, manganese sand, hydrotalcite, raw fly ash, as well as calcined modified fly ash, NaOH modified fly ash, and Ca(OH)2 modified fly ash were added to the two types of acidic mine wastewater at a dosage of 20 g / L, and stirred for 12 h.
[0049] Different added materials affect SO4 2- Concentration of 1000 mg·L -1 Acidic mine wastewater and SO4 2- Concentration of 1000 mg·L -1 The concentrations of Fe and Mn were both 100 mg·L⁻¹ -1 SO4 in acidic mine wastewater2- Removal effect as Figure 11 As shown, the results indicate that Ca(OH)2 modified fly ash has a positive effect on SO42-. 2- The simultaneous removal of Fe and Mn yields the best results.
[0050] Example 5
[0051] Preparation of high-concentration acidic mine wastewater treatment materials: The collected fly ash was dried at 100℃, then passed through a 100-mesh sieve, and then mixed with calcium ash at a 1:1 ratio. The mixture was placed in a co-rotating drum mixer and mixed for 3 hours. Then it was placed in a tubular resistance furnace and heated to 700℃ at a heating rate of 10℃ / min. The furnace was calcined at 700℃ for 2 hours and then naturally cooled to room temperature.
[0052] Calcination modified fly ash: The collected fly ash is dried at 100℃, passed through a 100-mesh sieve, placed in a tubular resistance furnace, and heated to 700℃ at a heating rate of 10℃ / min. It is then calcined at 700℃ for 2 hours and naturally cooled to room temperature.
[0053] NaOH modified fly ash: The collected fly ash was dried at 100℃, passed through a 100-mesh sieve, mixed with sodium ash at a 1:1 ratio, and placed in a co-rotating drum mixer for 3 hours. Then it was placed in a tubular resistance furnace, and the furnace temperature was raised to 700℃ at a heating rate of 10℃ / min. The furnace was then calcined at 700℃ for 2 hours and allowed to cool naturally to room temperature.
[0054] Prepare a solution with an Fe concentration of 100 mg·L -1 For acidic mine wastewater: Weigh 0.482g of FeCl3·6H2O into a beaker, add distilled water and stir thoroughly until completely dissolved. Transfer all the liquid in the beaker to a 1000mL volumetric flask, then add distilled water to the volumetric flask until it reaches 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0055] Configure Mn concentration to 100 mg·L -1 For acidic mine wastewater: Weigh 0.229g of MnCl2 into a beaker, add distilled water and stir thoroughly until completely dissolved. Transfer all the liquid in the beaker to a 1000mL volumetric flask, then add distilled water to the volumetric flask until it reaches 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0056] The concentrations of Fe and Mn were both 100 mg·L⁻¹. -1For acidic mine wastewater: Weigh 0.482g of FeCl3·6H2O and 0.229g of MnCl2 into beakers, add distilled water and stir thoroughly until completely dissolved. Transfer all the liquid in the beakers to a 1000mL volumetric flask, add distilled water to the volumetric flask until it reaches 1000mL, and then add concentrated nitric acid to adjust the pH to 1.
[0057] The prepared high-concentration acidic mine wastewater treatment material was added to the three types of acidic mine wastewater at a dosage of 20 g / L and stirred for 12 h.
[0058] Manganese sand, raw fly ash, calcined modified fly ash, NaOH modified fly ash, and Ca(OH)2 modified fly ash were added to the three types of acidic mine wastewater at a dosage of 20 g / L, and stirred for 12 h.
[0059] The effects of different materials on increasing the pH of three types of acidic mine wastewater, such as... Figure 12 As shown in the figure, the results indicate that Ca(OH)2 modified fly ash has the best effect on increasing the pH of acidic mine wastewater.
[0060] The present invention has been described in detail above with reference to preferred embodiments and exemplary examples. However, it should be noted that these specific embodiments and examples are merely illustrative explanations of the present invention and do not constitute any limitation on the scope of protection of the present invention. Various improvements, equivalent substitutions, or modifications can be made to the technical content and implementation methods of the present invention without departing from the spirit and scope of protection of the present invention, and all such modifications fall within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.
Claims
1. A high-concentration acidic mine wastewater treatment material, which is obtained by calcining fly ash and Ca(OH)2 at a high temperature of 700℃; The weight ratio of fly ash to Ca(OH)2 is 1:1; The roasting process includes: The temperature was increased to 700℃ at a heating rate of 5~10℃ / min, and then calcined at 700℃ for 2 hours. The fly ash is obtained by collecting fly ash from a coal-fired power plant, drying it at 90~110℃, and then passing it through an 80~100 mesh sieve. The Ca(OH)2 mentioned is analytical grade Ca(OH)2; Fly ash and Ca(OH)2 are placed in a co-rotating drum mixer and mixed for 2-3 hours. Then, they are calcined at 700℃ and allowed to cool naturally to room temperature after calcination.
2. A method for preparing a high-concentration acidic mine wastewater treatment material as described in claim 1, characterized in that, The method includes the following steps: (1) Collection and pretreatment of raw materials: fly ash is collected from the power plant, dried and sieved; (2) Raw material compounding and calcination: The sieved fly ash is thoroughly mixed with analytical grade Ca(OH)2, and then calcined at a high temperature of 700℃ and then cooled naturally after calcination; The weight ratio of fly ash to Ca(OH)2 is 1:1; The fly ash is obtained through the following methods: Fly ash is collected from coal-fired power plants, dried at 90-110℃, and then passed through an 80-100 mesh sieve.
3. The application of the high-concentration acidic mine wastewater treatment material as described in claim 1, characterized in that, The treatment material is used for the simultaneous removal of multiple metals and inorganic salts from high-concentration acidic mine wastewater. The multiple metals include iron ions and manganese ions, and the inorganic salt ions include sulfate ions.